Guinea pig urine darkens when it's exposed to the air as it dries, so some color is nothing to worry about. The urine of young pigs dries darker and oranger than that of older pigs. And since it's hard to tell whether color is accurately reproduced in a photograph, there's no way to know whether that's oxidized urine or urine with a bit of blood in it.

The characteristic symptoms of stones are hunching and squeaking when peeing or pooping, particularly when pooping.

A UTI can also cause a bit of bleeding, but if the pig has a UTI, the urine will probably have a stronger odor than GP urine usually does.

He is younger than 1 year old.But I think he is also older than 6 months old.He had the urine after I gave banana peel. Now, his urine looks normal.He hunching while pooping sometimes.He doesn’t squeak when pooping or peeing.Yes, the urine has a stronger odor sometimes.I think the cause of stronger odor is they pee a certain fleece a lot.